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Castillo-Ruiz M, Negrete C, Espinoza JP, Martínez I, Daille LK, González C, Rodríguez B. Antibiofilm Effects of Modifying Polyvinylidene Fluoride Membranes with Polyethylenimine, Poly(acrylic acid) and Graphene Oxide. Polymers (Basel) 2024; 16:3418. [PMID: 39684163 DOI: 10.3390/polym16233418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2024] [Revised: 11/26/2024] [Accepted: 12/02/2024] [Indexed: 12/18/2024] Open
Abstract
Biofouling in membrane filtration systems poses significant operational challenges, leading to decreased permeate flux. The aim of this work was to study the anti-biofilm properties of new nanofiltration membranes produced via layer-by-layer, LBL, assembly by coating a polyvinylidene fluoride (PVDF) support with a polyethylenimine (PEI) and poly(acrylic acid)/graphene oxide (PAA-GO) mixture. The membranes were characterized according to contact angle, scanning electron microscopy (SEM), atomic force microscopy and their Z-potential. Biofilm quantification and characterization were carried out using crystal violet staining and SEM, while bacterial viability was assessed by using colony-forming units. The membrane with three bilayers ((PAA-PEI)3/PVDF) showed a roughness of 77.78 nm. The incorporation of GO ((GO/PAA-PEI)3/PVDF) produced a membrane with a smoother surface (roughness of 26.92 nm) and showed salt rejections of 16% and 68% for NaCl and Na2SO4, respectively. A significant reduction, ranging from 82.37 to 77.30%, in biofilm formation produced by S. aureus and E. coli were observed on modified membranes. Additionally, the bacterial viability on the modified membranes was markedly reduced (67.42-99.98%). Our results show that the modified membranes exhibited both antibiofilm and antimicrobial capacities, suggesting that these properties mainly depend on the properties of the modifying agents, as the initial adherence on the membrane surface was not totally suppressed, but the proliferation and formation of EPSs were prevented.
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Affiliation(s)
- Mario Castillo-Ruiz
- Escuela de Tecnología Médica, Facultad de Ciencias de la Salud, Universidad Bernardo O'Higgins, General Gana 1702, Santiago 8370854, Chile
- Escuela de Química y Farmacia, Facultad de Medicina, Universidad Andres Bello, Sazié 2320, Santiago 8370134, Chile
| | - Constanza Negrete
- Facultad de Ciencias Naturales, Matemáticas y del Medioambiente, Universidad Tecnológica Metropolitana, Las Palmeras 3360, Ñuñoa 7800003, Chile
| | - Juan Pablo Espinoza
- CIBQA, Facultad de Ciencias de la Salud, Universidad Bernardo O'Higgins, Fábrica 1865, Santiago 8320000, Chile
| | - Iván Martínez
- Departamento de Ciencias Químicas y Biológicas, Facultad de Ciencias de la Salud, Universidad Bernardo O'Higgins, General Gana 1702, Santiago 8370854, Chile
| | - Leslie K Daille
- Centro GEMA-Genómica, Ecología & Medio Ambiente, Universidad Mayor, Camino La Pirámide 5750, Santiago 8580745, Chile
| | - Christopher González
- CIRENYS, Escuela de Química y Farmacia, Facultad de Ciencias Médicas, Universidad Bernardo O'Higgins, General Gana 1702, Santiago 8370854, Chile
| | - Bárbara Rodríguez
- CIRENYS, Escuela de Química y Farmacia, Facultad de Ciencias Médicas, Universidad Bernardo O'Higgins, General Gana 1702, Santiago 8370854, Chile
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Basualdo J, Iocoli GA, Gómez MA, Zabaloy MC. Dairy effluent management systems as a potential persistence source of Shiga toxin-producing Escherichia coli (STEC) strains. Rev Argent Microbiol 2024:S0325-7541(24)00119-6. [PMID: 39516110 DOI: 10.1016/j.ram.2024.09.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 08/01/2024] [Accepted: 09/24/2024] [Indexed: 11/16/2024] Open
Abstract
Shiga toxin-producing Escherichia coli (STEC) is a group of pathogenic enterobacteria of significant public health importance due to their association with highly prevalent human diseases. STEC is ubiquitous in livestock environments, and its presence in the environment emphasizes the importance of properly managing agricultural effluents to reduce health risks from contamination. In order to detect STEC in the effluent treatment systems of two dairy farms ("A" and "B") in the southwest of Buenos Aires province, samples ("A", n=88; "B", n=72) were taken at two different times of the year (winter and spring) and at various points in the treatment systems. Analysis markers for virulence genes (stx, eae, saa, and ehxA) revealed the presence of STEC in 13.1% of the samples, showing an increase in spring and differences between dairy farms possibly related to their maintenance conditions. After manure, sediments showed the highest proportion of STEC-positive samples, which is relevant due to the ability of these strains to survive in the environment through biofilm formation. Eight genetic profiles were identified among all STEC-positive samples, which are associated with STEC strains that can cause hemolytic uremic syndrome (HUS) and other gastrointestinal diseases. This demonstrates the role of dairy farm environments in the region as reservoirs of pathogenic STEC strains and their impact on public health.
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Affiliation(s)
- Jessica Basualdo
- Departamento de Agronomía, Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina
| | - Gastón A Iocoli
- Departamento de Agronomía, Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS), Departamento de Agronomía, Universidad Nacional del Sur, Bahía Blanca, Argentina
| | - Marisa A Gómez
- Departamento de Agronomía, Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina
| | - María Celina Zabaloy
- Departamento de Agronomía, Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS), Departamento de Agronomía, Universidad Nacional del Sur, Bahía Blanca, Argentina.
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Zhang R, Wang Y. EvgS/EvgA, the unorthodox two-component system regulating bacterial multiple resistance. Appl Environ Microbiol 2023; 89:e0157723. [PMID: 38019025 PMCID: PMC10734491 DOI: 10.1128/aem.01577-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2023] Open
Abstract
IMPORTANCE EvgS/EvgA, one of the five unorthodox two-component systems in Escherichia coli, plays an essential role in adjusting bacterial behaviors to adapt to the changing environment. Multiple resistance regulated by EvgS/EvgA endows bacteria to survive in adverse conditions such as acidic pH, multidrug, and heat. In this minireview, we summarize the specific structures and regulation mechanisms of EvgS/EvgA and its multiple resistance. By discussing several unresolved issues and proposing our speculations, this review will be helpful and enlightening for future directions about EvgS/EvgA.
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Affiliation(s)
- Ruizhen Zhang
- MoE Key Laboratory of Evolution and Marine Biodiversity, College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Yan Wang
- MoE Key Laboratory of Evolution and Marine Biodiversity, College of Marine Life Sciences, Ocean University of China, Qingdao, China
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
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Bera P, Wasim A, Ghosh P. Interplay of cell motility and self-secreted extracellular polymeric substance induced depletion effects on spatial patterning in a growing microbial colony. SOFT MATTER 2023; 19:8136-8149. [PMID: 37847026 DOI: 10.1039/d3sm01144e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2023]
Abstract
Reproducing bacteria self-organize to develop patterned biofilms in various conditions. Various factors contribute to the shaping of a multicellular bacterial organization. Here we investigate how motility force and self-secreted extracellular polymeric substances (EPS) influence bacterial cell aggregation, leading to phase-separated colonies using a particle-based/individual-based model. Our findings highlight the critical role of the interplay between motility force and depletion effects in regulating phase separation within a growing colony under far-from-equilibrium conditions. We observe that increased motility force hinders depletion-induced cell aggregation and phase segregation, necessitating a higher depletion effect for highly motile bacteria to undergo phase separation within a growing biofilm. We present a phase diagram illustrating the systematic variation of motility force and repulsive mechanical force, shedding light on the combined contributions of these two factors: self-propulsive motion and aggregation due to the depletion effect, resulting in the presence of small to large bacterial aggregates. Furthermore, our study reveals the dynamic nature of clustering, marked by changes in cluster size over time. Additionally, our findings suggest that differential dispersion among the components can lead to the localization of EPS at the periphery of a growing colony. Our study enhances the understanding of the collective dynamics of motile bacterial cells within a growing colony, particularly in the presence of a self-secreted polymer-driven depletion effect.
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Affiliation(s)
- Palash Bera
- Tata Institute of Fundamental Research Hyderabad, Telangana 500046, India
| | - Abdul Wasim
- Tata Institute of Fundamental Research Hyderabad, Telangana 500046, India
| | - Pushpita Ghosh
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Kerala, 695551, India.
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Abstract
Microbial communities are complex living systems that populate the planet with diverse functions and are increasingly harnessed for practical human needs. To deepen the fundamental understanding of their organization and functioning as well as to facilitate their engineering for applications, mathematical modeling has played an increasingly important role. Agent-based models represent a class of powerful quantitative frameworks for investigating microbial communities because of their individualistic nature in describing cells, mechanistic characterization of molecular and cellular processes, and intrinsic ability to produce emergent system properties. This review presents a comprehensive overview of recent advances in agent-based modeling of microbial communities. It surveys the state-of-the-art algorithms employed to simulate intracellular biomolecular events, single-cell behaviors, intercellular interactions, and interactions between cells and their environments that collectively serve as the driving forces of community behaviors. It also highlights three lines of applications of agent-based modeling, namely, the elucidation of microbial range expansion and colony ecology, the design of synthetic gene circuits and microbial populations for desired behaviors, and the characterization of biofilm formation and dispersal. The review concludes with a discussion of existing challenges, including the computational cost of the modeling, and potential mitigation strategies.
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Affiliation(s)
- Karthik Nagarajan
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Congjian Ni
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Ting Lu
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.,National Center for Supercomputing Applications, Urbana, Illinois 61801, United States
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